The invention relates to substituted 3-phenyl-5-alkoxy-1,3,4-oxadiazol-2-ones which have an inhibitory effect on the hormone-sensitive lipase HSL.
Certain 5-alkoxy-1,3,4-oxadiazol-2-ones having an ortho-substituted phenyl ring as substituent or having fused-on five- or six-membered rings have anthelmintic (DE-A 26 04 110) and insecticidal action (DE-A 26 03 877, EP-B 0 048 040, EP-B 0 067 471).
Certain 5-phenoxy-1,3,4-oxadiazol-2-ones having an ortho-substituted phenyl ring as substituent have endoparasiticidal action (EP-A 0 419 918).
It is an object of the present invention to provide compounds having an inhibitory effect on the hormone-sensitive lipase HSL.
This object was achieved with the substituted 3-phenyl-5-alkoxy-1,3,4-oxadiazol-2-ones of the formula 1, 
in which
R1 is C1-C6-alkyl or C3-C9-cycloalkyl, where both groups are unsubstituted or mono- or polysubstituted by Oxe2x80x94C1-C4-alkyl, Sxe2x80x94C1-C4-alkyl, N(C1-C4-alkyl)2 and/or phenyl which for its part may be mono- or polysubstituted by halogen, C1-C4-alkyl, Oxe2x80x94C1-C4-alkyl, nitro, CF3, and
R2 and R3 independently of one another are hydrogen, C6-C10-aryl, C3-C8-cycloalkyl, optionally C1-C4-alkyl-substituted C6-C10-aryloxymethyl, Oxe2x80x94C3-C8-cycloalkyl, Oxe2x80x94C6-C10-aryl or O-benzyl, unsubstituted or mono- or polysubstituted by halogen, CF3 or C1-C4-alkyl, Oxe2x80x94C1-C6-alkyl which is mono- or polysubstituted by fluorine, C6-C10-aryl or amino, where amino for its part may be mono- or polysubstituted by C1-C4-alkyl, are SO2xe2x80x94NHxe2x80x94C1-C6-alkyl, unsubstituted or substituted by N(C1-C6-alkyl)2, are SO2xe2x80x94NH-(2,2,6,6-tetramethylpiperidin4-yl), SO2xe2x80x94NHxe2x80x94C3-C8-cycloalkyl, unsubstituted or mono- or polysubstituted by C1-C4-alkyl, are SO2xe2x80x94N(C1-C6-alkyl)2 or COX,
where X is Oxe2x80x94C1-C6-alkyl, NHxe2x80x94C1-C6-alkyl, NHxe2x80x94C3-C8-cycloalkyl or N(C1-C6-alkyl)2, and
N(C1-C6-alkyl)2 may also be pyrrolidino, piperidino, morpholino, thiomorpholino or piperazino -which may be unsubstituted or substituted by C1-C4-alkyl, benzyl, C6-C10-aryl, COxe2x80x94C1-C4-alkyl, COxe2x80x94C6-C10-aryl, COxe2x80x94Oxe2x80x94C1-C4-alkyl, SO2xe2x80x94C1-C4-alkyl or SO2xe2x80x94C6-C10-aryl,
with the proviso that R2 and R3 are not simultaneously hydrogen, and their physiologically acceptable salts and optical isomers.
The aryl radicals mentioned can be unsubstituted or mono- or polysubstituted by C1-C4-alkyl, C1-C4-alkoxy, halogen, trifluoromethyl. The cycloalkyl radicals mentioned can be unsubstituted or mono- or polysubstituted by C1-C4-alkyl, and the alkyl radicals mentioned can be substituted by hydroxyl, di-C1-C4-alkylamino and fluorine. Halogen denotes fluorine, chlorine, bromine, preferably fluorine and chlorine.
Preference is given to substituted 3-phenyl-5-alkoxy-1,3,4-oxadiazol-2-ones of the formula 1, in which one of the radicals R2 or R3 is hydrogen.
Particular preference is given to substituted 3-phenyl-5-alkoxy-1,3,4-oxadiazol-2-ones of the formula 1, in which
R1 is C1-C6-alkyl which may be unsubstituted or substituted by phenyl.
Particular preference is furthermore given to substituted 3-phenyl-5-alkoxy-1,3,4-oxadiazol-2-ones of the formula 1, in which
R2 and R3 independently of one another are hydrogen, C6-C10-aryl,
C3-C8-cycloalkyl, unsubstituted or C1-C4-alkyl-substituted C6-C10-aryloxymethyl, Oxe2x80x94C3-C8-cycloalkyl, Oxe2x80x94C6-C10-aryl or O-benzyl, unsubstituted or mono- or polysubstituted by C1-C4-alkyl or halogen, Oxe2x80x94C1-C6-alkyl which is mono- or polysubstituted by fluorine, C6-C10-aryl or amino, where amino for its part may be mono- or polysubstituted by C1-C4-alkyl, are SO2xe2x80x94NHxe2x80x94C1-C6-alkyl, optionally substituted by N(C1-C6-alkyl)2, are SO2xe2x80x94NHxe2x80x94(2,2,6,6-tetramethylpiperidin4-yl), SO2xe2x80x94NHxe2x80x94C3-C8-cycloalkyl, substituted by C1-C4-alkyl, are SO2xe2x80x94N(C1-C6-alkyl)2 or COxe2x80x94N(C1-C6-alkyl)2, and N(C1-C6-alkyl)2 may also be piperidino, morpholino or piperazino which can be unsubstituted or substituted by C1-C4-alkyl.
Very particular preference is also given to substituted 3-phenyl-5-alkoxy-1,3,4-oxadiazol-2-ones of the formula 1, in which
R2 is hydrogen, C6-C10-aryl, Oxe2x80x94C6-C10-aryl, unsubstituted or C1-C4-alkyl-substituted C6-C10-aryloxymethyl, O-benzyl, is Oxe2x80x94C1-C6-alkyl which is mono- or polysubstituted by fluorine or amino, where amino for its part may be mono- or polysubstituted by C1-C4-alkyl, is Oxe2x80x94C3-C8-cycloalkyl which is unsubstituted or mono- or polysubstituted by C1-C4-alkyl, and
R3 is hydrogen, C6-C10-aryl, C3-C8-cycloalkyl, Oxe2x80x94C3-C8-cycloalkyl or Oxe2x80x94C6-C10-aryl which is unsubstituted or mono- or polysubstituted by C1-C4-alkyl or halogen, is Oxe2x80x94C1-C6-alkyl which is mono- or polysubstituted by fluorine, is SO2xe2x80x94NHxe2x80x94C1-C6-alkyl, unsubstituted or substituted by N(C1-C6-alkyl)2, is SO2xe2x80x94NH-(2,2,6,6-tetramethylpiperidin-4-yl), SO2xe2x80x94NHxe2x80x94C3-C8-cycloalkyl, mono- or polysubstituted by C1-C4-alkyl, is SO2xe2x80x94N(C1-C6-alkyl)2 or COxe2x80x94N(C1-C6-alkyl)2, and
N(C1-C6-alkyl)2 is also piperidino, morpholino or piperazino, which may be unsubstituted or substituted by C1-C4-alkyl.
Very particular preference is given to substituted 3-phenyl-5-alkoxy-1,3,4-oxadiazol-2-ones of the formula 1, in which
R1 is methyl, ethyl, butyl, isopropyl or benzyl and
R2 is hydrogen, trifluoromethoxy, trifluorobutoxy, 3,3,5,5-tetramethylcyclohexyloxy, benzyloxy, phenoxy, phenyl, 2-diethylaminoethyloxy or 3-methylphenoxymethyl, and
R3 is hydrogen, trifluoromethoxy, 3,3,5,5-tetramethylcyclohexyloxy, phenoxy, 4-chlorophenoxy, cyclohexyl, phenyl, morpholinosulfonyl, 3,3,5-trimethylcyclohexylaminosulfonyl, 2,2,6,6-tetramethylpiperidin-4-yl-aminosulfonyl, 2-(diisopropylaminoethyl)aminosulfonyl, 4-methylpiperazin-1-yl-sulfonyl, 3,3-dimethylpiperidinocarbonyl or 3,5-dichlorophenoxy.
Very particular preference is furthermore given to substituted 3-phenyl-5-alkoxy-1,3,4-oxadiazol-2-ones of the formula 1, in which
R1 is methyl, ethyl, butyl, isopropyl or benzyl and
R2 is hydrogen, trifluoromethoxy, 3,3,5,5-tetramethylcyclohexyloxy, 3 benzyloxy or phenoxy and
R3 is hydrogen, trifluoromethoxy, 3,3,5,5-tetramethylcyclohexyloxy, phenoxy, cyclohexyl, phenyl, morpholinosulfonyl or 3,3,5-trimethylcyclohexylaminosulfonyl.
The compounds of the formula 1 according to the invention have an unexpected inhibitory effect on the hormone-sensitive lipase HSL, an allosteric enzyme in adipocytes which is inhibited by insulin and responsible for the degradation of fats in fat cells and thus for the transfer of fat components into the bloodstream. Thus, an inhibition of this enzyme corresponds to an insulin-like effect of the compounds according to the invention which in the end results in a reduction of free fatty acids in the blood and of blood sugar. Accordingly, they can be used for metabolic disorders such as, for example, for non-insulin-dependent diabetes mellitus, for diabetic syndrome and in cases where the pancreas is damaged directly.
The compounds of the formula 1 according to the invention can be prepared by different routes using methods known per se. 
For example, the substituted 3-phenyl-5-alkoxy-1,3,4-oxadiazol-2-ones of the formula 1 can be prepared by reacting hydrazines of the formula 2 with chloroformic esters of the formula 3 or other reactive carbonic acid ester derivatives, in which R1, R2 and R3 are as defined above, to give compounds of the formula 4 which are acylated with phosgene, carbonyldiimidazole or diphosgene and cyclized to give the compounds of the formula 1. Since in general acids are liberated in these reactions, it is recommended to add bases such as pyridine, triethylamine, aqueous sodium hydroxide solution or alkali metal carbonates to accelerate the reaction. The reactions can be carried out in wide temperature ranges. In general, it has been found to be advantageous to carry out the reactions at from 0xc2x0 C. to the boiling point of the solvent used. Suitable solvents are, for example, methylene chloride, THF, DMF, toluene, ethyl acetate, n-heptane, dioxane, diethylether.
The hydrazines of the formula 2 are commercially available or can be prepared by known methods, for example by diazotization of the corresponding anilines 
with subsequent reduction or by nucleophilic substitution of appropriately substituted phenyl derivatives 6(X=F, Cl, Br, I, OSO2CF3) with hydrazine hydrate. Such suitable phenyl derivatives can be nitro-substituted halogenated benzenes, preferably fluoro- and chloronitrobenzenes, from which, at a suitable point in the synthesis path, the compounds according to the invention can be prepared by reduction and reaction with acylating or alkylating agents, such as, for example, acid chlorides, anhydrides, isocyanates, chloroformic esters, sulfonyl chlorides or alkyl halides and arylalkyl halides.
The invention also relates to the use of compounds of the formula I in the form of their racemates, racemic mixtures and pure enantiomers, and to their diastereomers and mixtures thereof.
Pharmaceutically acceptable salts are particularly suitable for medical applications because of their greater solubility in water compared with the initial compounds on which they are based. These salts must have a pharmaceutically acceptable anion or cation. Suitable pharmaceutically acceptable acid addition salts of the compounds of the formula I are salts of inorganic acids such as hydrochloric acid, hydrobromic acid, phosphoric, metaphosphoric, nitric and sulfuric acids, and organic acids such as, for example, acetic acid, benzenesulfonic, benzoic, citric, ethanesulfonic, fumaric, gluconic, glycolic, isethionic, lactic, lactobionic, maleic, malic, methanesulfonic, succinic, p-toluenesulfonic, tartaric and trifluoroacetic acids. It is particularly preferred to use the chloride for medical purposes. Suitable pharmaceutically acceptable basic salts are ammonium salts, alkali metal salts (such as sodium and potassium salts) and alkaline earth metal salts (such as magnesium and calcium salts).
Salts with a pharmaceutically unacceptable anion likewise fall within the scope of the invention as useful intermediates for preparing or purifying pharmaceutically acceptable salts and/or for use in non-therapeutic, for example in vitro, applications.
The term xe2x80x9cphysiologically functional derivativexe2x80x9d used herein refers to any physiologically tolerated derivative of a compound according to the invention, for example an ester, which is able on administration to a mammal, such as, for example, to humans, to form (directly or indirectly) such a compound or an active metabolite thereof.
A further aspect of this invention is the use of prodrugs of compounds of the formula I. Such prodrugs can be metabolized in vivo to a compound of the formula I. These prodrugs may themselves be active or not.
The compounds of the formula I may also exist in various polymorphous forms, for example as amorphous and crystalline polymorphous forms. All polymorphous forms of the compounds of the formula I fall within the scope of the invention and are a further aspect of the invention.
All references hereinafter to xe2x80x9ccompound(s) of the formula (I)xe2x80x9d refer to compound(s) of the formula (I) as described above and to the salts, solvates and physiologically functional derivatives thereof as described herein.
The amount of a compound of the formula (I) necessary to achieve the desired biological effect depends on a number of factors, for example the specific compound chosen, the intended use, the mode of administration and the clinical condition of the patient. The daily dose is generally in the range from 0.3 mg to 100 mg (typically from 3 mg to 50 mg) per day and per kilogram body weight, for example 3-10 mg/kg/day. An intravenous dose may be, for example, in the range from 0.3 mg to 1.0 mg/kg, which can suitably be administered as infusion of 10 ng to 100 ng per kilogram and per minute. Infusion solutions suitable for these purposes may contain, for example, from 0.1 ng to 10 mg, typically from 1 ng to 10 mg, per milliliter. Single doses may contain, for example, from 1 mg to 10 g of the active ingredient. Thus, ampoules for injections may contain, for example, from 1 mg to 100 mg, and single dose formulations which can be administered orally, such as, for example, tablets or capsules, may contain, for example, from 1.0 to 1000 mg, typically from 10 to 600 mg. In the case of pharmaceutically acceptable salts, the above weight data are based on the weight of the free compound derived from the salt. The compounds of the formula (I) can be used for prophylaxis or therapy of the abovementioned states themselves as compound, but they are preferably in the form of a pharmaceutical composition with a compatible carrier. The carrier must, of course, be compatible in the sense of compatibility with other ingredients of the composition and not be harmful to the patient""s health. The carrier may be a solid or a liquid or both and is preferably formulated with the compound as single dose, for example as tablet, which may contain from 0.05% to 95% by weight of the active ingredient. Further pharmaceutically active substances may likewise be present, including further compounds of the formula (I). The pharmaceutical compositions according to the invention may be produced by one of the known pharmaceutical methods which essentially consists of mixing the ingredients with pharmacologically acceptable carriers and/or excipients.
Pharmaceutical compositions according to the invention are those suitable for oral, rectal, topical, peroral (for example sublingual) and parenteral (for example subcutaneous, intramuscular, intradermal or intravenous) administration, although the most suitable mode of administration depends in each individual case on the nature and severity of the condition to be treated and on the nature of the compound of the formula (I) used in each case. Coated formulations and coated slow-release formulations also fall within the scope of the invention. Acid- and gastric fluid-resistant formulations are preferred. Suitable gastric fluid-resistant coatings comprise cellulose acetate phthalate, polyvinyl acetate phthalate, hydroxypropylmethylcellulose phthalate and anionic polymers of methacrylic acid and methyl methacrylate.
Suitable pharmaceutical compounds for oral administration may be in the form of separate units such as, for example, capsules, cachets, pastilles or tablets, each of which contains a defined amount of the compound of the formula (I); as powder or granules; as solution or suspension in an aqueous or nonaqueous liquid; or as an oil-in-water or water-in-oil emulsion. These compositions may, as already mentioned, be prepared by any suitable pharmaceutical method which includes a step in which the active ingredient and the carrier (which may consist of one or more additional ingredients) are brought into contact. In general, the compositions are produced by uniform and homogeneous mixing of the active ingredient with a liquid and/or finely dispersed solid carrier, after which the product is shaped if necessary. Thus, for example, a tablet can be produced by compressing or shaping the powder or granules of the compound, where appropriate with one or more additional ingredients. Compressed tablets may be produced by tabletting the compound in free-flowing form, such as, for example, a powder or granules, where appropriate mixed with a binder, lubricant, inert diluent and/or one (or more) surface-active/dispersing agents in a suitable machine. Shaped tablets can be produced by shaping, in a suitable machine, the compound which is in powder form and has been moistened with an inert liquid diluent.
Pharmaceutical compositions suitable for peroral (sublingual) administration comprise suckable tablets which contain a compound of the formula (I) with a flavoring, normally sucrose, and gum arabic or tragacanth, and pastilles which contain the compound in an inert base such as gelatin and glycerol or sucrose and gum arabic.
Suitable pharmaceutical compositions for parenteral administration comprise preferably sterile aqueous preparations of a compound of the formula (I), which are preferably isotonic with the blood of the intended recipient. These preparations are preferably administered intravenously, although administration can also take place by subcutaneous, intramuscular or intradermal injection. These preparations can preferably be produced by mixing the compound with water and making the resulting solution sterile and isotonic. Injectable compositions according to the invention generally contain from 0.1 to 5% by weight of the active compound.
Suitable pharmaceutical compositions for rectal administration are preferably in the form of single-dose suppositories. These can be produced by mixing a compound of the formula (I) with one or more conventional solid carriers, for example cocoa butter, and shaping the resulting mixture.
Suitable pharmaceutical compositions for topical use on the skin are preferably in the form of an ointment, cream, lotion, paste, spray, aerosol or oil. Carriers which can be used are petrolatum, lanolin, polyethylene glycols, alcohols and combinations of two or more of these substances. The active ingredient is generally present in a concentration of from 0.1 to 15% by weight of the composition, for example from 0.5 to 2%.
Transdermal administration is also possible. Suitable pharmaceutical compositions for transdermal applications may be in the form of single plasters which are suitable for long-term close contact with the patient""s epidermis. Plasters of this type suitably contain the active ingredient in an aqueous solution which is buffered where appropriate, dissolved and/or dispersed in an adhesive or dispersed in a polymer. A suitable active ingredient concentration is about 1% to 35%, preferably about 3% to 15%. As a particular option, the active ingredient can be released by electrotransport or iontophoresis as described, for example, in Pharmaceutical Research, 2 (6): 318 (1986).
The activity of the compounds of the formula 1 according to the invention was examined using the following enzyme test system:
Preparation of the Partially Purified HSL:
Isolated rat fat cells are obtained from epididymal fatty tissue from untreated male rats (Wistar, 220-250 g) by collagenase treatment according to published processes (e.g. S. Nilsson et al., Anal. Biochem. 158, 1986, 399-407; G. Fredrikson et al., J. Biol. Chem. 256, 1981, 6311-6320; H. Tornquist et al., J. Biol. Chem. 251, 1976, 813-819). The fat cells from 10 rats are washed three times by flotation with 50 ml each of homogenization buffer (25 ml tris/HCI, pH 7.4, 0.25 M sucrose, 1 mM EDTA, 1 mM DTT, 10 xcexcg/ml of leupeptin, 10 xcexcg/ml of antipain, 20 xcexcg/ml of pepstatin) and finally taken up in 10 ml of homogenization buffer. The fat cells are homogenized in a Teflon-in-glass homogenizer (Braun-Melsungen) by 10 strokes at 1500 rpm and 15xc2x0 C. The homogenizate is centrifuged (Sorvall SM24 tubes, 5000 rpm, 10 min, 4xc2x0 C). The bottom layer between the overlying fatty layer and the pellet is removed and the centrifugation is repeated. The bottom layer resulting from this is centrifuged again (Sorvall SM24 tubes, 20,000 rpm, 45 min, 4xc2x0 C). The bottom layer is removed and treated with 1 g of heparin-Sepharose (Pharmacia Biotech, CL-6B, washed 5xc3x97 with 25 mM tris/HCl, pH 7.4, 150 mM NaCl). After incubation for 60 min at 4xc2x0 C. (shake at intervals of 15 min), the batch is centrifuged (Sorvall SM24 tubes, 3000 rpm, 10 min, 4xc2x0 C.). The supernatant is brought to pH 5.2 by addition of glacial acetic acid and incubated at 4xc2x0 C. for 30 min. The precipitates are collected by centrifugation (Sorvall SS34, 12,000 rpm, 10 min, 4xc2x0 C.) and suspended in 2.5 ml of 20 mM tris/HCl, pH 7.0, 1 mM EDTA, 65 mM NaCl, 13% sucrose, 1 mM DTT, 10 xcexcg/ml of leupeptin/pepstatin/antipain. The suspension is dialyzed overnight at 4xc2x0 C. against 25 mM tris/HCl, pH 7.4, 50% glycerol, 1 mM DTT, 10 xcexcg/ml of leupeptin, pepstatin, antipain and then applied to a hydroxylapatite column (0.1 g per 1 ml of suspension, equilibrated with 10 mM potassium phosphate, pH 7.0, 30% glycerol, 1 mM DTT). The column is washed with four volumes of equilibration buffer at a flow rate of 20 to 30 ml/h. The HSL is eluted with a volume of equilibration buffer which contains 0.5 M potassium phosphate, then dialyzed (see above) and concentrated 5 to 10 times by ultrafiltration (Amicon Diaflo PM 10 filter) at 4xc2x0 C. The partially purified HSL can be stored at xe2x88x9270xc2x0 C. for 4 to 6 weeks.
Assay:
For the preparation of the substrate, 25-50 xcexcCi of [3H]trioleoylglycerol (in toluene), 6.8 xcexcMol of unlabeled trioleoylglycerol and 0.6 mg of phospholipids (phosphatidylcholine/phosphatidylinositol 3:1 w/v) are mixed, dried over N2 and then taken up in 2 ml of 0.1 M KPi (pH 7.0) by ultrasonic treatment (Branson 250, microtip, setting 1-2, 2xc3x971 min at a 1 min interval). After addition of 1 ml KPi and fresh ultrasonic treatment (4xc3x9730 sec on ice at 30 sec intervals), 1 ml of 20% BSA (in KPi) is added (final concentration of trioleoylglycerol 1.7 mM). For the reaction, 100 xcexcl of substrate solution are pipetted into 100 xcexcl of HSL solution (HSL prepared as above, diluted in 20 mM KPi, pH 7.0, 1 mM EDTA, 1 mM DTT, 0.02% BSA, 20 xcexcg/ml of pepstatin, 10 xcexcg/ml of leupeptin) and incubated at 37xc2x0 C. for 30 min. After addition of 3.25 ml of methanol/chloroform/heptane (10:9:7) and of 1.05 ml of 0.1 M K2CO3, 0.1 M boric acid (pH 10.5), the batch is well mixed and finally centrifuged (800xc3x97g, 20 min). After phase separation, one equivalent of the upper phase (1 ml) is taken and the radioactivity is determined by liquid scintillation measurement.
Analysis:
Substances are customarily tested in four independent batches. The inhibition of the enzymatic activity of the HSL by a test substance is determined by comparison with an uninhibited control reaction. The IC50 value is calculated by means of an inhibition curve using at least 10 concentrations of the test substance. For the analysis of the data, the software package GRAPHIT, Elsevier-BIOSOFT is used.
In this test, the compounds had the following activity: